Temporal and Spatial Variation Characteristics of Soil Temperature in Cotton Fields under Different Cropping Systems

[Objective] Soil temperature affects the biochemical processes of crops; therefore, elucidating its spatial and temporal distribution characteristics in different cropping systems is an essential part of understanding how to boost cotton yield potential. [Method] In 2016 and 2017, continuous, real-time soil temperature monitoring was conducted at a depth of 10-110 cm in three cropping systems, including monoculture cotton (MC), wheat/intercropped cotton (WIC), and wheat/direct-seeded cotton (WDC). We investigated the growth process and various agronomic traits. [Result] Different cotton soil temperatures were found between MC and doubled in late May, indicating about 1-3 ℃ higher in the former during the symbiotic period. In early July, the cotton soil temperature of the double-cropping systems at 10-40 cm was higher than that of the MC, but showed the opposite at 40-110 cm. In early August, the differences in soil temperature reduced among the three cropping systems, while the soil temperature of the MC was still slightly lower than that of the double-cropping systems. After mid-September, the soil temperature of the double-cropping systems was lower than that of the MC. The soil temperature mainly influenced the duration of cotton seedling to squaring, and flowering to the boll-opening period. At the same time, there was a subtle effect on the squaring to flowering and boll period. In general, higher average soil temperatures were associated with shorter growth period durations. During the same period, the lowest daily soil temperature of the double-cropping systems occurred about one hour earlier than in the MC; however, the highest daily temperature appeared at the same time. There was a linear relationship between accumulated soil temperature and biomass at different layers across cropping systems. [Conclusion] Controlling the timing and quantity of irrigation water can assist agronomic practices by alleviating the effect of soil temperature on cotton growth. Increased accumulative soil temperature is beneficial to cotton emergence and boll opening in double-cropping systems. This study provides a theoretical basis for rational allocation and management of different cropping systems.     

单作棉和3-2式麦棉生态系统作物共生期的光温特点

种植模式影响到农作物生存的微环境,3-2式麦棉套种模式在小麦与棉花共生期间,由于小麦的遮挡作用,使得棉田土壤接受的太阳辐射减少,土壤温度低,且单作与套作种植模式的光合有效辐射(PAR)和土壤温度具有各自的时空变化,在麦棉复合种植模式中,地上10cm的PAR是:棉行间>棉行上>麦棉间>麦行上;而单作棉模式是:棉行间>棉行上。两种种植模式土壤温度也存在差异,在空间上存在垂直分异和水平分异,在时间上存在时间分异。土层深度是影响土壤温度另一个重要因子。上层土壤温度在一天的不同时段上差异比较明显。40cm的土壤温度波动很小,60cm处的土壤温度基本上平稳。     

麦棉两熟双高产条件下麦棉复合根系生长的时空动态分布

在麦棉两熟双高产条件下,以单作棉和单作麦为对照,利用根钻与DT-SCAN扫描相结合的方法研究麦棉复合根系群体生长的时空动态分布,结果表明,套作棉和单作棉的根长和根长密度、根表面积以及根系平均直径均随生育进程呈单峰曲线,套作棉40 cm以下各土层根系根长和根长密度、根表面积的衰退速率在盛花期后明显低于单作棉,根系     

南疆枣树￣棉花间作对土壤微生物区系及代谢熵的影响

通过大田试验和实验室测定,研究南疆枣树-棉花间作对土壤微生物性状的影响。在阿克苏地区阿瓦提县巴格托拉克乡采集枣树￣棉花间作、纯枣林及单作棉田土样,测定比较细菌、放线菌和真菌三大类群微生物及氮素生理群菌群数量、微生物代谢熵的变化特征。结果表明,不同种植模式土壤微生物数量分布有明显差异。枣树￣棉花间作土壤细菌、放线菌、真菌和微生物总数总体呈现出显著低于单作棉田,降低幅度最大的位点在西侧冠下区(W80);较纯枣林增加,增加幅度最大的是东侧冠下区(E80)。枣树-棉花间作系统比单作棉田土壤氨化细菌、硝化细菌数量有较大提高,反硝化细菌数量明显下降,氨化细菌、反硝化细菌相比纯枣林均为增加。间作系统内在枣树行的东、西两侧冠下区与近冠区及L1(0~20 cm)、L2(20~40 cm)及L3(40~60 cm)各层次土壤中的微生物数量都呈现出较大差异,具有明显的水平和垂直方向空间变异性。不同种植模式下土壤微生物代谢熵(q CO2)依次为纯枣林枣树￣棉花间作单作棉花。不同种植模式下土壤微生物Shannon多样性、均匀度指数与微生物数量具有相似的变化特性。相关性分析表明,有机碳、全氮、碱解氮含量及p H与微生物多样性呈极显著正相关(P0.01),与代谢熵则呈极显著负相关。研究结果证明,微生物群落多样性及代谢熵对间作种植模式响应灵敏,反映出枣树和棉花间作系统地下部分存在明显的竞争作用,影响土壤微生物的群落。     

Intercropping maize and wheat with conservation agriculture principles improves water harvesting and reduces carbon emissions in dry areas

In arid and populated areas or countries, water shortage and heavy carbon emissions are threatening agricultural sustainability with food security severely, and becoming a major issue. It is unclear whether improved farming systems can be developed to tackle those issues through a sustainable agriculture. Here three farming practices that have proven to be essential and successful, which were: (a) crop intensification through strip intercropping, (b) water harvesting through conservation tillage; and (c) carbon sequestration through improved crop residue management options, were integrated in one cropping system. We hypothesize that the integrated system allows the increase of crop yields with improved water use efficiency, while reducing carbon emissions from farming. The hypothesis was tested in field experiments at Hexi Corridor (37°96′N, 102°64′E) in northwest China. We found that the integrated system increased soil moisture (mm) by 7.4% before sowing, 10.3% during the wheat–maize co-growth period, 8.3% after wheat harvest, and 9.2% after maize harvest, compared to the conventional sole cropping systems. The wheat/maize intercrops increased net primary production by 68% and net ecosystem production by 72%; and when combined with straw mulching on the soil surface, it decreased carbon emissions by 16%, compared to the monoculture maize without mulch. The wheat/maize intercrops used more water but increased grain yields by 142% over the monoculture wheat and by 23% over the monoculture maize, thus, enhancing water use efficiency by an average of 26%. We conclude that integrating strip intercropping, conservation tillage as well as straw mulching in one cropping system can significantly boost crop yields, improve the use efficiency of the limited water resources in arid areas, while, lowering the carbon emissions from farming. The integrated system may be considered in the development of strategies for alleviating food security issues currently experienced in the environment-damaged and water-shortage areas.     

麦棉套种对棉行太阳辐射和温度的影响

对３－２式麦棉套种预留棉行的小气候效应进行研究在明，小麦对预留棉行有根强的遮荫作用；致使齐穗期预留棉行中央的光合有效辐射较冠层减少３０％，太阳总辐射削减１９％；小麦黄熟前，预留棉行内风速较一熟棉田小，午后气温也较一熟棉田低；共生前期麦套露地棉田地温较一熟棉田低，小麦黄熟后较一熟棉田高，而麦套地膜棉田的地温一直较一熟棉田高。降低小麦株高，留足预留棉行，麦套棉地膜覆盖。加强小麦生育后期的水分管理，都有利于减轻麦棉套种的不利和小气候的影响。     

麦棉两熟种植模式对棉仁脂肪及蛋白质代谢的影响

研究麦棉两熟种植模式影响棉仁脂肪及蛋白质代谢机制,可为我国麦棉两熟棉区在稳定棉花产量和品质的基础上提高棉籽品质提供理论依据。试验于2012年和2013年在江苏省大丰市稻麦原种场进行,以泗杂3号(中晚熟品种)和中棉所50(早熟品种)棉花品种为材料,以单作棉为对照(CK),设置棉花生产上常用的麦套移栽棉(IC)、麦后移栽棉(TC)和麦后直播棉(DC)麦棉种植模式,研究麦棉两熟不同种植模式对棉仁脂肪和蛋白质的累积动态、关键酶活性及其相互关系的影响。结果表明:(1)两熟棉棉仁脂肪含量皆较CK低,IC、TC和DC呈依次下降的趋势;IC和TC棉仁蛋白质含量皆高于CK,DC低于CK;中棉所50棉仁脂肪和蛋白质含量均略高于泗杂3号。(2)两熟棉棉仁磷脂酸磷酸酯酶(PPase)和6-磷酸葡萄糖脱氢酶(G6PDH)活性低于CK,丙酮酸羧化酶(PEPC)活性高于CK;IC、TC棉仁谷氨酰胺合成酶(GS)和谷氨酸合酶(GOGAT)活性高于CK,DC低于CK;中棉所50棉仁具有较高的PPase、G6PDH、GS和GOGAT活性,PEPC活性稍低于泗杂3号。(3)棉仁最终脂肪含量与棉仁代谢过程中PPase、G6PDH活性呈极显著正相关,与PEPC活性呈极显著负相关;棉仁最终蛋白质含量与G6PDH活性及GS、GOGAT活性分别呈显著和极显著正相关。总之,在我国麦棉两熟棉区选择应用中熟棉花品种、麦套移栽方式可以在稳定棉花产量和品质的基础上提高棉籽品质。     

小麦不同品种间作和混作对麦蚜发生量的影响

通过小麦不同品种的间作、混作,以期用其本身物种的多样性控制麦蚜发生数量。实验通过将5个小麦品种在田间间作和混作组合,以单作小麦品种为对照,在小麦关键期和麦蚜盛发期调查麦蚜发生数量,用蚜量比值法比较不同小麦品种间的抗虫性,用麦蚜发生量比较不同组合间的差异并对比其防治效应。结果表明：各单作品种的感虫程度为高感：石7816>95-108>兰天13,感虫：兰天6>兰天1;在扬花期和灌浆期所有间、混作组合麦蚜发生量至少显著低于其中一种单作品种(P<0.05);在扬花期和灌浆期,除兰天1/石7816、兰天13/95-108、兰天6/95-108和兰天1/95-108这4个组合出现了防治效应负增长外,所有间、混作组合均对麦蚜有防治效果,间作的平均防治效应为12.94%,变化范围为-24.67%~44.33%,混作的平均防治效应为28.92%,变化范围为1.67%~61.33%,防治效应最好的组合均是兰天1/兰天6/兰天13/95-108/石7816,防治效应分别为44.33%和61.33%。研究结果表明不同小麦品种间作、混作大部分对麦蚜的发生量有较好的防治效果。     

Effects of Cotton/Sesame Intercropping Patterns on Crop Growth and Yield

[Objective] Intercropping as an intensive planting method, could increase the utilization ratio of land and resources. The study aimed to explore the advantages and disadvantages of cotton/sesame intercropping, and then find out the best planting pattern of cotton/sesame intercropping. [Method] Equidistant row monocropping cotton (Tc₁), wide narrow row monocropping cotton (Tc₂) and monocropping sesame (Ts) were used as control. We designed three intercropping patterns as follows: 1-1 pattern (cotton row spacing was 80 cm, one row of sesame was planted in the two row spacing), 2-1 pattern (cotton grown in wide-narrow-row, one row of sesame was planted in the wide row spacing), and 2-2 pattern (cotton grown in wide-narrow-row, two rows of sesame were planted in the wide row spacing). The effects of different intercropping patterns on cotton/sesame yield, yield components, leaf area index dynamic change and dry matter accumulation were investigated. The land equivalent ratio was used as an index to assess the land use efficiency. [Result] The results showed that cotton/sesame yield were significantiy affected by different intercropping patterns. However, the seed cotton yield decreased only slightly in 2-1 intercropping pattern. Two years average showed that, the seed cotton yield, plant height, boll number of per plant and boll weight in 1-1 pattern were reduced by 17.3%, 7.9%, 19.7% and 7.9% compared with Tc₁, respectively. In the treatment of 2-2 model, which reduced by 16.4%, 5.81%, 14.8% and 6.2% in comparison with Tc_2. But in the intercropping systems, the mixed yield and comprehensive economic benefit of cotton and sesame were higher than those of cotton and sesame monoculture. The leaf area index of the group and the total amount of dry matter accumulation in unit area increased significantly under cotton/sesame intercropping systems. The land equivalent ratios in 2015 and 2016 were from 1 to 1.24 and 0.91 to 1.16, respectively. [Conclusion] Under different cotton/sesame intercropping systems, the mixed yield and total economic benefit were higher than that of monocropping cotton or sesame. The 2-1 cotton/sesame intercropping pattern occupied the most optimal production performance and easy to cultivate, which was the practicable intercropping patterns in sustainable development.     

Nitrogen use efficiency of cotton (Gossypium hirsutum L.) as influenced by wheat–cotton cropping systems

Wheat–cotton rotations largely increase crop yield and improve resources use efficiency, such as the radiation use efficiency. However, little information is available on the nitrogen (N) utilization and requirement of cotton under wheat–cotton rotations. This study was to determine the N uptake and use efficiency by evaluating the cotton (Gossypium hirsutum L.) N use and the soil N balances, which will help to improve N resource management in wheat–cotton rotations. Field experiments were conducted during 2011/2012 and 2012/2013 growing seasons in the Yangtze River region in China. Two cotton cultivars (Siza 3, mid-late maturity with 130 days growth duration; CCRI 50, early maturity with 110 days growth duration) were planted under four cropping systems including monoculture cotton (MC), wheat/intercropped cotton (W/IC), wheat/transplanted cotton (W/TC) and wheat/direct-seeded cotton (W/DC). The N uptake and use efficiency of cotton were quantified under different cropping systems. The results showed that wheat–cotton rotations decreased the cotton N uptake through reducing the N accumulation rate and shortening the duration of fast N accumulation phase as compared to the monoculture cotton. Compared with MC, the N uptake of IC, TC and DC were decreased by 12.0%, 20.5% and 23.4% for Siza 3, respectively, and 7.3%, 10.7% and 17.6% for CCRI 50, respectively. Wheat–cotton rotations had a lower N harvest index as a consequence of the weaker sink capacity in the cotton plant caused by the delayed fruiting and boll formation. Wheat–cotton rotations used N inefficiently relative to the monoculture cotton, showing consistently lower level of the N agronomic use efficiency (NAE), N apparent recovery efficiency (NRE), N physiological efficiency (NPE) and N partial factor productivity (NPFP), particularly for DC. Relative to the mid–late maturity cultivar of Siza 3, the early maturity cultivar of CCRI 50 had higher N use efficiency in wheat–cotton rotations. An analysis of the crop N balance suggested that the high N excess in preceding wheat (Triticum aestivum L.) in wheat–cotton rotations led to significantly higher N surpluses than the monoculture cotton. The N management for the cotton in wheat–cotton rotations should be improved by means of reducing the base fertilizer input and increasing the bloom application.     

晋西幼龄苹果×大豆间作的土壤中水分、养分空间分布特征及对大豆的影响

为了研究幼龄苹果(Malus pumila)×大豆(Glycine max)间作系统中土壤水分、养分的空间分布特征及其对大豆生长和产量的影响,选取晋西黄土地区具有典型代表性的幼龄苹果×大豆间作模式作为研究对象,对苹果×大豆间作系统及大豆单作系统（对照）的土壤水分、养分含量进行了定位监测。结果表明：（1）在垂直方向上,土壤水分含量随着土壤深度的增加而逐渐增加,土壤养分含量随着土壤深度的增加而逐渐减小;（2）在水平方向上,随着与树行距离的增加,土壤水分含量呈现递增的分布特征,土壤养分含量呈现高低高的分布特征;（3）与大豆单作系统相比,间作系统的土壤水分、养分含量出现不同程度的降低,整体上均表现为负效应;（4）苹果×大豆间作系统中苹果树与大豆间的土壤水分、养分竞争对大豆植株生长发育造成了较大影响,土壤水分含量、速效磷含量和全氮含量是影响大豆产量的主要因素,影响的主要区域在苹果树行两侧1.5 m的范围内;（5）建议采取适当的调控和管理措施缓解种间水肥竞争提高大豆的产量,以获取更多的经济收益。     

棉田玉米螟的发生为害及分布型研究

在河南棉区,第１代玉米螟在棉田为害严重,第２、３代很少为害棉花。不同类型田相比麦棉套种田受害较重。采用频次比较,聚集度指标判别等方法对棉田玉米螟的空间分布型进行了探讨。结果表明,麦棉套田螟卵块呈均分布,其余田块玉米螟卵、幼虫均属聚集分布。     

集约栽培条件下间套作的光能利用理论发展及其应用

通过连续3年小麦、玉米带状间套作的试验,比较了作物在间套种植与单作种植时对光能利用的差异。结果表明:小麦玉米间套作复合群体LAI妻3的日数比单作小麦、玉米提高2.03倍和29.2%,叶-日积提高1.2倍和13.1%,截获的太阳辐射能高54.75%和2.32%,透光率高38.7%和26.4%。间套作的小麦、玉米的LAIs/LAI在生长盛期比单作小麦、玉     

根钻和图像法测定棉麦套种及单种作物根长密度的精确性研究

【目的】研究田间根钻取样结合计算机图像软件分析方法测定棉麦套种及单种作物根长密度的精确性。【方法】结合田间根钻取样,分别用图像法(DT-SCAN图像软件分析法)和直尺法(常规人工直尺测量法)测量根长密度,通过2002―2013年试验获得的3423对根长密度数据分析图像法的精确性,使用根均方差描述图像法测定值(模拟值)与直尺法测定值(观测值)之间的一致性。【结果】2种方法测定根长密度的相关性较好,图像法的精确性较高。对可能影响图像法精确性的因素分析表明:(1)在不同种植模式下图像法的精确性表现为小麦单种模式棉花单种模式麦棉套种模式;(2)随着土壤深度增加,图像法的精确性增加;(3)在麦棉套种模式下图像法的精确性从麦幅到棉幅逐渐提高,在小麦单种模式下行上大于行间,在棉花单种模式下行上小于行间;(4)在棉花开花前图像法的精确性表现为棉花单种模式大于麦棉套种模式,在棉花开花后表现为棉花单种模式小于麦棉套种模式。【结论】田间根钻取样结合计算机图像软件分析方法测定棉麦套(单)种作物根长密度的精确性较高,该方法成本低、测定速度快,能更好地扫描并分析计算棉花的细小侧根,具有较强的先进性和较高的可靠性。     

根系不同分隔方式下油菜和鹰嘴豆对小麦锰营养的影响

通过根系分隔盆栽试验,研究了油菜和鹰嘴豆对小麦生长及锰营养的影响.结果表明:与油菜或鹰嘴豆混作能显著改善小麦生长及锰营养,其地上部干质量和吸收锰量均以根系不分隔处理显著高于根系完全分隔处理,但油菜和鹰嘴豆的生长受小麦抑制,表现为不分隔处理地上部干质量及吸锰量显著低于完全分隔.不施锰小麦/油菜和小麦/鹰嘴豆混作体系中,根系不分隔处理小麦根区土壤DTPA-Mn含量显著高于其他分隔方式,且油菜或鹰嘴豆地上部植株锰含量显著高于相应的混作小麦,在锰胁迫条件下,油菜和鹰嘴豆根系活化的土壤锰可被小麦吸收利用.因此与油菜或鹰嘴豆混作是改善小麦锰营养的有效途径之一.     

裸苗移栽棉花缓苗期抗氧化酶活性和叶绿素含量的变化特点

 2007年在一熟棉田设裸苗移栽、钵苗移栽和直播3个处理,在麦棉两熟裸苗移栽棉田设置地膜覆盖和不覆盖两个处理,在移栽后40 d内分次取样测定棉花功能叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT) 活性和叶绿素含量。结果表明,移栽棉花由于移栽时根系受损,存在明显的缓苗期,缓苗期内功能叶片三种酶活性和叶绿素含量变化规律均表现为先升高而后下降或趋于平稳变化;CAT、POD较SOD对逆境的反应敏感,其活性当处于逆境时快速升高,逆境解除时就迅速下降;地膜覆盖有利于缩短移栽缓苗期,促进棉苗早发。     

河南植棉区施氮量对麦棉两熟产量及氮肥利用率的影 响简

 研究了河南植棉区麦棉两熟施氮量对两季产量和氮肥利用率的影响。结果表明,施氮能显著提高小麦产量、总有效穗数和穗粒数,籽粒千粒重随施氮量增加而降低;商丘和内黄试验点小麦最高产量所需的施氮量分别为201.4 kg·hm^-2和187.2 kg·hm^-2,经济最佳施氮量分别为163.0 kg·hm^-2和134.9 kg·hm^-2。施氮也能显著提高棉花产量和单株成铃数;适量施氮可提高铃重;商丘和内黄试验点棉花最高产量所需的施氮量分别为244.4 kg·hm^-2和224.2 kg·hm^-2,经济最佳施氮量分别为225.9 kg·hm-2和207.0 kg·hm^-2。小麦氮肥利用率以施氮量180 kg·hm^-2最高。麦棉两季氮肥利用率,商丘试验点随施氮量增加而降低;内黄试验点以施氮量390 kg·hm^-2最高。小麦、棉花氮肥偏生产力、农学利用率均随施氮量增加而降低。     

长期连作对南疆棉田土壤物理性质影响的研究

为研究连作年限对棉田土壤物理性质的影响,以南疆连作3年、10年、15年的棉田为研究对象,对不同种植制度条件下棉田土壤物理性状各指标进行测定与分析。结果表明：棉花连作10年以后,水稻→小麦-绿肥→棉花种植制度棉田水分状况优于水稻→棉花种植制度;棉花连作3年、15年,与水稻→棉花种植制度相比,水稻→小麦-绿肥→棉花种植制度土壤容重分别减轻2.5%、2.8%;土壤孔隙度在不同连作年限之间存在极显著差异;从种植制度及连作年限对棉田土壤物理性质的影响综合分析,在南疆极端干旱条件下适应棉花长期连作的种植制度为水稻→小麦-绿肥→棉花,棉花连作年限不宜超过15年。     

麦棉套作技术之初步研究

1973～1978年的田间试验结果说明:小麦茬棉田以采用麦棉套作较好,套作的合理配置方式以小麦播幅占地40%,预留棉行占地60%(畦宽4.0尺,小麦播幅占1.6尺,预留棉行占2.4尺,以下同)较恰当。这种配置方式六年小麦亩产418.0～611.0斤,平均491.5斤,比单作(麦棉轮作)减产15.8%。麦棉套作又以套作移栽的棉花产量最高,1975～1978四年亩产     

小麦/燕麦根系不同分隔方式及施锰对小麦锰营养的影响

通过根系分隔的根盒试验,研究了小麦/燕麦间作体系中根系不同分隔方式及土壤施锰对小麦锰营养的影响。结果表明：与不施锰肥处理相比,施用锰肥显著提高了小麦的地上部干重和吸锰量,小麦/燕麦根系不同分隔方式对小麦的地上部干重、锰浓度和吸锰量均无显著影响。不同作物品种吸收活化土壤锰的能力不同,表现为燕麦＞小麦;9023＞川麦28;坝莜4号＞坝莜3号。但在本试验条件下,与燕麦间作没能改善小麦的锰营养,可能是作物种植密度大,而根系生长空间较小造成的,其具体原因还有待于进一步研究